Frequency Response Virtual Instrument

It is fairly easy to determine the frequency response (magnitude) of a circuit in the lab using just a function generator and a multimeter. However, it is much more convenient to automate the measurements and record the measured values using LabVIEW. Having the results stored in the computer memory provides the additional advantage of being able to perform subsequent analysis of the data. In this lab we will use the frequency response VI in LabVIEW to determine the frequency response of two filter circuits. The Frequency Response VI communicates with the function generator and the multimeter to measure a circuit's frequency response. The VI executes the following steps:

1. Configure the multimeter to measure AC voltage.
2. For Loop: for i=0:N-1 Step through frequencies
   • Set frequency of function generator.
   • Read the AC Voltage from the multimeter.
   • Form the ratio of the output voltage amplitude to the input voltage amplitude.
   • Output the measured frequency response value to the plots on the front panel.

At each frequency, a measurement of the frequency response is made and the value plotted on the front panel. At the end of the ``for loop," N measurements of the frequency response have been made.